Cat nutrition attracts an enormous amount of marketing noise. Strip that away and the underlying biology is well understood — here's what actually holds up.
Cats are obligate carnivores — this is non-negotiable biology, not a preference. Unlike dogs, which are functional omnivores, and unlike humans, cats cannot synthesize several essential compounds — taurine, arachidonic acid, and usable vitamin A among them — from plant material. Without adequate dietary taurine specifically, cats develop dilated cardiomyopathy (a form of heart failure) and retinal degeneration leading to blindness. A vegan or vegetarian diet is not a viable option for a cat regardless of intent; it will cause serious, progressive harm.
The wet vs. dry debate, resolved practically: Wet food runs 75-80% moisture, which meaningfully supports kidney function and urinary tract health — closer to what a cat would get from prey in the wild, which is itself mostly water by weight. It also tends to have a higher protein-to-carbohydrate ratio than dry food. Dry food's advantages are convenience, shelf stability, and a modest dental-health benefit from the mechanical action of chewing kibble; its main drawback is lower moisture, meaning cats on all-dry diets need reliable, ample water access to compensate. For most cats, a mixed approach — wet food for hydration and protein density, dry available for grazing and convenience — balances these tradeoffs well.
Reading a label in under 30 seconds: the first ingredient should be a named animal protein — chicken, salmon, turkey — not a vague term like "meat meal" or "animal by-products," which can source from inconsistent or lower-quality material. Look for an AAFCO statement confirming the food is "complete and balanced" for the cat's life stage. On a dry-matter basis, adult maintenance food should run 30%+ protein, kitten food 35%+. Red flags: corn or other grain-heavy fillers listed as a primary ingredient, artificial colors (cats don't perceive color, so this exists purely for owners), and BHA/BHT preservatives, which some studies link to health concerns at high exposure.
Portioning by the numbers: an average indoor adult cat needs roughly 200-250 calories per day, which translates to about 1/3 to 1/2 cup of dry food or one standard 5.5oz can of wet food — but this varies significantly by brand, so check the calorie density on your specific food's label rather than assuming. Body condition scoring is more reliable than a scale: you should be able to feel the ribs with light pressure but not see them prominently, and the cat should have a visible waist tuck when viewed from above.
Foods that are genuinely toxic — memorize this list:
🚫 Onions and garlic (in any form, including powder) — destroy red blood cells, causing anemia
🚫 Chocolate — theobromine toxicity, dose-dependent but no "safe" amount
🚫 Grapes and raisins — linked to acute kidney failure in cats and dogs alike
🚫 Xylitol (artificial sweetener, common in sugar-free products) — causes rapid, severe liver failure
🚫 Alcohol — dangerous even in small quantities relative to body size
🚫 Raw bread dough — yeast continues expanding in the warm stomach environment, plus alcohol byproduct from fermentation
🚫 Caffeine — cardiac and neurological effects, similar risk profile to chocolate
Safe occasional treats, if you want to share:
✅ Plain cooked chicken or turkey, no seasoning, no bones
✅ Small amounts of cooked salmon or tuna (limit frequency — excess fish can affect vitamin E levels and, in some cases, contribute to a condition called steatitis)
✅ Small cubes of cantaloupe or watermelon
✅ Fully cooked eggs
✅ Plain canned pumpkin puree (unsweetened, no spices) — genuinely useful for mild digestive upset too
Hydration deserves more attention than it usually gets. Cats evolved from desert-dwelling ancestors and retain an unusually low thirst drive relative to their fluid needs — they don't reliably "drink to thirst" the way dogs do. This matters because chronic mild dehydration is a major contributing factor to chronic kidney disease, the leading cause of death in cats over 10. Practical fixes: a fountain-style water bowl (moving water draws more interest from many cats), multiple water stations around the house, and wide, shallow bowls, since some cats experience "whisker fatigue" — discomfort from whiskers repeatedly brushing the sides of a narrow bowl — and will avoid drinking as a result. Adding a splash of water to dry food, or leaning more on wet food generally, both meaningfully boost daily fluid intake.
Feeding outdoor or community cats specifically: wet food is preferable in cold weather since it delivers more usable calories per feeding and is easier to eat quickly. Serve on disposable plates for hygiene and easy cleanup. Feed on a consistent schedule so you (or other caretakers) can monitor who's showing up and who's not — an absence is often the first sign something's wrong. Remove uneaten food after about 30 minutes to avoid drawing in pests, and avoid leaving food out overnight unless it's inside a covered, weatherproof feeding station.